field of air pollution requested by the DG Environment. The objectives of this study were to:
• Have an assessment of presently available scientific information on the feasibility of utilising remote sensing techniques in the implementation of existing legislation, and describe opportunities for realistic streamlining of monitoring in air quality and emissions, based on greater use of remote sensing.
• Have recommendations for the next policy cycle on the use of remote sensing through development of appropriate provisions and new concepts, including, if appropriate, new environmental objectives, more suited to the use of remote sensing.
• Have guidance on how to effectively engage with GMES and other initiatives in the air policy field projects Satellite remote sensing of the troposphere is a rapidly developing field. Today several satellite sensors are in orbit that measure trace gases and aerosol properties relevant to air quality. Satellite remote sensing data have the following unique properties:
• Near-simultaneous view over a large area;
• Global coverage;
• Good spatial resolution.
The properties of satellite data are highly complementary to ground-based in-situ networks, which provide detailed measurements at specific locations with a high temporal resolution.
Although satellite data have distinct benefits, the interpretation is often less straightforward as compared to traditional in-situ measurements.
Maps of air pollution measured from space are widespread in the scientific community as well as in the media, and have had a strong impact on the general public and the policy makers. The next step is to make use of satellite data in a quantitative way. Applications based solely on satellite data are foreseen, however an integrated approach using satellite data, ground-based data and models combined with data assimilation, will make the best use of the satellite remote-sensing potential, as well as of the synergy with ground-based observations.